I don't think it's really fair to try to critique the gait of a BYB special with poor conformation, but here goes.
I have never studied conformation or paid much attention to it, and what I know I learnt from reading critiques on this forum, and asking the occasional question. Basically, I consider myself a pet-owner who likes to train with her dogs, not an expert, so take what I say in that view.
Leo is really cute, first off! Seems to have a really nice, fluffy, soft coat. But from this very short video of her, I would say she does not even move LIKE a GSD - her gait reminds me of my mixed-breed Rotti-ish rescue. Nice, happy bouncy trot - compared to Gryffon's gait: even in a trot, he seems to just flow over the landscape like water. No exagerated flying trot effect, just a sense of smoothness and and minimum effort. Your girl looks like she is just skipping along, happy and carefree - makes for a nice picture, but not what one expects from a GSD.
One aspect of conformation in Gryff that contributes to that effect of smoothness is his rear leg angulation, as compared to Keeta's, whose rear legs are a lot straighter, more like Leo's.
I honestly don't know enough about structure to be able to say what other aspects of conformation contribute to the GSD characteristic signature gait.
Now if some conformation folks jump in and and contradict everything I said, I'd listen to them instead of me.